github.com/eclipse/paho.mqtt.golang example

mqtt_test.go

package mqtt_test

import (
        "sync"
        "testing"

        mqtt "github.com/eclipse/paho.mqtt.golang"
)

func TestMqttPubSub(t *testing.T) {

        const TOPIC = "mytopic/test"

        opts := mqtt.NewClientOptions().AddBroker("tcp://localhost:1883")

        client := mqtt.NewClient(opts)
        if token := client.Connect(); token.Wait() && token.Error() != nil {
                t.Fatal(token.Error())
        }

        var wg sync.WaitGroup
        wg.Add(1)

        if token := client.Subscribe(TOPIC, 0, func(client mqtt.Client, msg mqtt.Message) {
                if string(msg.Payload()) != "mymessage" {
                        t.Fatalf("want mymessage, got %s", msg.Payload())
                }
                wg.Done()
        }); token.Wait() && token.Error() != nil {
                t.Fatal(token.Error())
        }

        if token := client.Publish(TOPIC, 0, false, "mymessage"); token.Wait() && token.Error() != nil {
                t.Fatal(token.Error())
        }
        wg.Wait()
}